A roadside bomb has killed 18 civilians and wounded five on a small bus on its way to a wedding in Afghanistan's Ghazni province, deputy provincial police chief Colonel Asadullah Ensafi has said.

The attack on Sunday occurred in the Andar district of the lawless province as the bus traveled from one village to another just before dusk.

The dead included 14 women, three men and one child, Ensafi said but noted there were no other details as the remote area is not easily accessible to security forces.

Andar is one of the few districts in Ghazni where the Taliban retain some measure of control and often attack security forces, mostly by laying bombs along roads.

The blast comes as Taliban fighters increased their attacks around the country to try and take advantage of the withdrawal of foreign forces, who handed over security responsibilities to the Afghans earlier this summer.

The UN said in the first six months of this year, 1,319 civilians were killed and 2,533 were wounded in the ongoing 12-year Afghan conflict. Most of their attacks involve suicide attackers or roadside bombs.

Another bomb targeting a group of soldiers killed a girl shopping in a market in the capital of Kabul on Sunday. Five soldiers were injured in that attack.